The amount of information transferred over the various local and global communications networks is growing at a staggering rate. A recent white paper published in 2008 by Cisco Systems Inc. entitled “Approaching the Zettabyte Era” predicts that global IP traffic will increase from about 10 exabytes per month in 2008 to over 40 exabytes per month in 2012. The rapid increase in global communication traffic has generated a need for faster and smaller communications components.
In November 2006 a group of leading communications companies promulgated a specification for a physically small optical transceiver capable of supporting data transfer rates of up to 40 Gbits per second. The latest update of the specification was issued in March 2009.
The specification defines an optical transceiver, comprising four independent optical transmit channels and four independent optical receive channels. Each transmit channel is required to be capable of transmitting data at up to 10 gigabits per second (Gbps). The specified transceiver is configured to multiplex the data from the four independent transmit channels and transmit the multiplexed data over a single mode fiber (SMF), hereinafter a “transmit fiber”, for a total aggregated transceiver transmission data rate of 40 Gbps. Each receive channel is required to be capable of receiving data at up to 10 gigabits per second (Gbps) for a total aggregated transceiver receive data rate of 40 Gbps. The transceiver is configured to receive data over a single SMF “receiver fiber” and demultiplex the received data to the four receive channels. The specified transceiver is designed to replace four standard SFP transceivers and occupy a space of only about 30% more than one of the standard SFP transceivers. It is referred to as a “Quad Small Form-factor Pluggable” optical module, and is commonly referred to by its acronym “QSFP”.